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  • C09K19/06—Non-steroidal liquid crystal compounds
  • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
  • C09K19/10—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings
  • C09K19/12—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings at least two benzene rings directly linked, e.g. biphenyls
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  • C09K19/06—Non-steroidal liquid crystal compounds
  • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
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  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
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  • C07C69/76—Esters of carboxylic acids having a carboxyl group bound to a carbon atom of a six-membered aromatic ring
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  • C07C69/76—Esters of carboxylic acids having a carboxyl group bound to a carbon atom of a six-membered aromatic ring
  • C07C69/94—Esters of carboxylic acids having a carboxyl group bound to a carbon atom of a six-membered aromatic ring of polycyclic hydroxy carboxylic acids, the hydroxy groups and the carboxyl groups of which are bound to carbon atoms of six-membered aromatic rings
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  • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
  • C09K19/06—Non-steroidal liquid crystal compounds
  • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
  • C09K19/10—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings
  • C09K19/14—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings linked by a carbon chain
  • C09K19/16—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings linked by a carbon chain the chain containing carbon-to-carbon double bonds, e.g. stilbenes
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  • C09K19/06—Non-steroidal liquid crystal compounds
  • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
  • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
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  • C09K19/00—Liquid crystal materials
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  • C09K19/06—Non-steroidal liquid crystal compounds
  • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
  • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
  • C09K19/3001—Cyclohexane rings
  • C09K19/3003—Compounds containing at least two rings in which the different rings are directly linked (covalent bond)
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  • C09K19/00—Liquid crystal materials
  • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
  • C09K19/42—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40
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  • C09K19/00—Liquid crystal materials
  • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
  • C09K19/42—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40
  • C09K19/46—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40 containing esters

Definitions

• the present invention relates to ferroelectric liquid crystal compositions and liquid crystal devices comprising the above compositions.
• Liquid crystal display devices most widely used presently are those utilizing nematic phase.
• twisted nematic (TN) liquid crystal devices decrease in contrast with an increase in the number of lines, so that it is practically impossible to fabricate large-capacity liquid crystal devices of this type with 2000 x 2000 lines.
• STN supertwisted nematic
• DSTN double supertwisted nematic
• liquid crystal display devices of the active matrix type wherein thin film transistors (TFT) are arranged on a substrate.
• TFT thin film transistors
• ferroelectric liquid crystal display devices are proposed [see N.A. Clark et al., Appl. Phys. Lett., 36, 899(1980)].
• the proposed device utilized the chiral smectic C phase, chiral smectic I phase of ferroelectric liquid crystals.
• the device can be given a great display capacity with an improved response speed since the memory property of the crystals is utilized. Further more, the device can be produced at a low cost since it does not need to use active components such as thin-film transistors.
• the ferroelectric liquid crystal display device also offers the wider field of view. Thus, the device appears very promising as a large capacity-display device having at least 2000 x 2000 lines.
• liquid crystal materials for use in the ferroelectric liquid crystal display device wherein smectic C phase is utilized must of course exhibit smectic C phase over a wide temperature range around room temperature and needs to fulfill various other requirements.
• the device for large capacity display must have high speed responsiveness, and from this viewpoint, the liquid crystal materials need to be highly amenable to spontaneous polarization and low in viscosity. Further to obtain satisfactory orientation and bistability when used for the liquid crystal cell, the liquid crystal material needs to exhibit the phase series of IAC (Isotropic-Smectic A-Smectic C), or INAC Clsotropic-Nematic-Smectic A-Smectic C), and the helical pitch of nematic phase and smectic C phase needs to be sufficiently larger than the cell length. It is also desired that the material be great in tilt angle which is relevant to the contrast and brightness of liquid crystal display. Moreover, it is required to optimize dielectric anisotropy, refractive index and specific resistance.
• the present invention has been accomplished in view of the above situation, and provides a ferroelectric liquid crystal composition having a wide operation temperature range, excellent orientation, excellent memory property and large tilt angle as well as exhibiting high-speed responsiveness at high temperature, and a liquid crystal display device comprising the above-mentioned composition.
• the present invention provides a ferroelectric liquid crystal composition
• a ferroelectric liquid crystal composition comprising at least one compound of the following formula (I): wherein R 1 is a straight or branched chain alkyl or alkoxy group having 1 to 15 carbon atoms, and are the same or different, a phenylene group which may be substituted by a halogen or a cyclohexylene group, X is a single bond or a vinyl or cyclopropylene group, Y is a methylene group or -COO- group, Z is a mono- , di- or trifluoromethyl group, m is an integer of 1 to 15 and R 2 is a straight or branched chain alkyl group having 1 to 15 carbon atoms or a phenyl group, and a base liquid crystal material.
• R 1 is a straight or branched chain alkyl or alkoxy group having 1 to 15 carbon atoms, and are the same or different, a phenylene group which may
• the base liquid crystal material comprises at least one compound of the following formula (II): wherein R 3 and R 4 are, the same or different, a straight or branched chain alkyl or alkyloxy group having 1 to 15 carbon atoms and k is an integer of 0 or 1 and/or at least one compound of the following formula (III): wherein R 5 and R 6 are, the same or different, a straight or branched chain alkyl or alkyloxy group having 1 to 15 carbon atom, and are, the same or different, a phenylene group which may be substituted by a halogen or a cyclohexylene group, 1, m and n each is an integer of 0 or 1 and the sum of 1, m and n is 1, 2 or 3.
• optically active compounds represented by the formula (I) include the isomers of trans-form and cis- form, both of which can be used for the present invention.
• the aforesaid isomers may be admixed for use.
• the straight or branched chain alkyl group having 1 to 15 carbon atoms include, e.g., methyl, ethyl, propyl, i-propyl, butyl, i-butyl, pentyl, 1- or 2-methylbutyl, hexyl, 1- or 3- methylpentyl, heptyl, 1-or 4-methylhexyl, octyl, 1-methylheptyl, nonyl, 1- or 6-methyloctyl, decyl, 1-methylnonyl, undecyl, 1-methyldecyl, dodecyl, 1-methylundecyl or the like.
• the branched chain alkyl or alkyloxy groups may contain an asymmetric carbon atom. Further, one or more hydrogen atoms in these alkyl or alkyloxy groups may be substitued with a fluorine atom, chlorine atom, bromine atom, cyano group, nitro group, trifluoromethyl group, methoxy group or the like.
• the phenylene group which may be substituted by a halogen with respect to the definition of or may be phenylene group or monofluorophenylene group.
• the compound (I) of the present invention can be prepared, e.g., by reacting the corresponding carboxylic acid with phosphorus pentachloride to convert into the carboxylic acide chloride, and reacting the resulting carboxylic acid chloride with sodium alkoxide as formed by the reaction of the corresponding optically active alcohol and sodium hydride.
• the reactions can be shown by the following chemical formulae.
• optically active alcohols to be used in the above reaction can be synthesized according to, e.g., Takashi Tsukamoto, Michinori Takeda, Masazoe Hayashi, Takashi Yamazaki & Tomoya Kitazume, "Fluorine Chemistry Discussion, XIII, Transactions” (1988), 4D, 112.
• the compounds (I) do not always exhibit a liquid crystal phase. However, the addition of the compounds (I) in a suitable amount to a nonchiral smectic liquid compound or its composition or chiral smectic liquid compound or its composition increases the spontaneous polarization and high-speed responsiveness.
• any of the optically active compounds (I) wherein Z is a mono- , di- or trifluoro-methyl group can be used, the one in which Z is a trifluoro-methyl group is more preferable.
• the ferroelectric liquid crystal composition contains the compound (I) usually in an amount of 0.1 to 30 wt.%, preferably 0.5 to 10 wt.%, more preferably 2.0 to 10 wt.% based on the total weight of the composition. If the amount is over 30 wt.%, there arises practical problems such that the compound added thereto is crystallized in the ferroelectric liquid crystal composition and the upper limit temperature decreases in the smectic C phase, whereas if the amount is less than 0.1 wt.%, fully improved responsiveness will not be available.
• the straight or branched chain alkyl group having I to 15 carbon atoms includes, e.g., methyl, ethyl, propyl, i-propyl, butyl, i-butyl, pentyl, 1-or 2-methylbutyl, hexyl, 1- or 3-methylpentyl, heptyl, 1-or 4-methylhexyl, octyl, 1-methylheptyl, nonyl, 1- or 6-methyloctyl, decyl, 1-methylnonyl, undecyl, 1-methyldecyl, dodecyl, 1-methylundecyl or the like.
• the branched chain alkyl or alkyloxy groups may contain an asymmetric carbon atom. Further, one or more hydrogen atoms in these alkyl or alkyloxy groups may be substituted with a fluorine atom, chlorine atom, bromine atom, cyano group, nitro group, trifluoromethyl group, methoxy group or the like.
• the compound (II) can be prepared, e.g., by the method disclosed in Zaschke, H,; Schubert, H.; Kuschel, F.; Dinger, F. and Demus, D.; DDR WP 95892.
• the compound (II) When the compound (II) is used as a base liquid crystal material, it can exhibit stable smectic C phase, and hence can produce a ferroelectric liquid crystal composition where a temperature range in the chiral smectic C phase is wide and responsive speed is high.
• the compounds (II) are used in a mixture thereof.
• the compound (II) occupies usually in the range of 30 to 99%, preferably 50 to 85% of the composition.
• the straight or branched chain alkyl group having 1 to 15 carbon atoms includes, e.g., methyl, ethyl, propyl, i-propyl, butyl, i-butyl, pentyl, 1-or 2-methylbutyl, hexyl, 1- or 3-methylpentyl, heptyl, 1-or 4-methylhexyl, octyl, 1-methylheptyl, nonyl, 1- or 6-methyloctyl, decyl, 1-methylnonyl, undecyl, 1-methyldecyl, dodecyl, 1-methylundecyl or the like.
• the branched chain alkyl or alkyloxy groups may contain an asymmetric carbon atom. Further, one or more hydrogen atoms in these alkyl or alkyloxy groups may be substituted with a fluorine atom, chlorine atom, bromine atom, cyano group, nitro group, trifluoromethyl group, methoxy group or the like.
• the phenylene group which may be substituted by a halogen as defined in the definition of or is also applicable to that of or of the compound (III).
• the compound (III) can be prepared, e.g., by the method disclosed in Gray, G.W.; Goodby. J. W.; Mol. Cryst. Liq. Cryst. 37, 157, (1976).
• the compound (III) When the compound (III) is used as a base liquid crystal material, it is effective for increasing the upper-limit temperature of chiral smectic C phase, widening the temperature range of the nematic phase and decreasing the temperature for crystallization.
• the compounds (III) are usually used in a mixture thereof.
• the compounds (III) to be contained are usually 5 to 99 wt.%, preferably 10 to 45 wt.% of the composition. If the concentration of the compound (III) is low, a satisfactory effect cannot be obtained, while high concentration causes unfavorable phenomena such as crystallization at low temperature, increase in viscosity or the like. Accordingly, the combination use of the compounds (III) and (II) is preferable.
• the ferroelectric liquid crystal composition may be prepared by adding, in a suitable amount, compounds other than the compounds (I), (II) and (III) such as: wherein R 7 and R 8 have the same meanings as defined for R 5 and R 6 and k is the same as defined above, or wherein R 9 and R 10 have the same meanings as defined for R 5 and R 6 and 1 and m have the same meanings as defined above, or wherein R 11 and R 12 have the same meanings as defined for R 5 and R 6 , and have the same meanings as defined for and and 1, m and n are the same as defined above.
• compounds other than the compounds (I), (II) and (III) such as: wherein R 7 and R 8 have the same meanings as defined for R 5 and R 6 and k is the same as defined above, or wherein R 9 and R 10 have the same meanings as defined for R 5 and R 6 and 1 and m have the same meanings as defined above, or wherein R 11 and R 12 have the same meanings as defined for R 5
• the amount of these compounds to be contained is usually less than 40 wt.% of the composition.
• the compounds (I) increase the spontaneous polarization and responsive speed of the ferroelectric liquid crystal composition.
• the compounds (II) widen the temperature range of the ferroelectric liquid crystal composition showing chiral smectic C phase and decrease viscosity.
• the compounds (III) widen the temperature range of the ferroelectric liquid crystal composition showing chiral smectic C phase and nematic phase and increase the tilt angle.
• the ferroelectric liquid crystal composition having various excellent characteristics can be prepared by mixing these compounds at a suitable ratio.
• the present invention further provides a liquid crystal device which comprises the ferroelectric liquid crystal composition disposed between a pair of electrodes.
• the device can be of known construction and fabricated with use of materials already known in the art.
• the cell length is preferably 0.8 to 10.0 ⁇ m, more preferably 1.2 to 6.0 ⁇ m.
• the liquid crystal device which is useful as a display device, is also advantageously usable as a liquid crystal shutter.
• Phosphorus pentachloride (0.4 g, 1.9 m mol) was added to 4'-n-octyloxy-biphenyl-4-carboxylic acid (0.5 g, 1.5 m mol), followed by heating.
• the reaction mixture was distilled under reduced pressure to remove phosphorus oxychloride and an excess of phosphorus pentachloride, affording 4'-n-octyloxy-biphenyl-4-carboxylic acid chloride.
• Phosphorus pentachloride (0.4 g, 1.9 m mol) was added to 4'-n-octyloxy-biphenyl-4-carboxylic acid (0.5 g, 1.5 m mol), followed by heating.
• the reaction mixture was distilled under reduced pressure to remove phosphorus oxychloride and an excess of phosphorus pentachloride, affording 4'-n-octyloxy-biphenyl-4-carboxylic acid chloride.
• (S)-1-trifluoromethyl-nonylalcohol 0.3 g, 1.5 m mol was dissolved in toluene (10 ml), to which sodium hydride (0.05 g, 2 m mol) was added. Unreacted sodium hydride was filtered off to obtain sodium (S)-1-trifluoromethyl-nonylalkoxide.
• the above acid chloride dissolved in toluene (10mi) was added to the resultant compound. The mixture was allowed to stand for 12 hours at room temperature, maintained for 3 hours at 80°C and cooled. This reaction mixture was then added to distilled water and extracted with ethyl ether.
• Liquid crystal compositions No. 7 to No. 9 were prepared, each of which has compositions shown in Table 2 and exhibits nonchiral smectic C phase.
• Ferroelectric liquid crystal display devices Nos. 10 to 19 shown in Table 3 were prepared by adding liquid crystal compositions Nos. 1 to 6 shown in Table 1 in an amount of 2 to 10 wt.% respectively to each of liquid crystal compositions Nos. 7 to 9.
• ferroelectric liquid crystal compositions include optically active compounds in a concentration of 2 to 10 wt.% which is relatively low, a helical pitch of nematic phase was larger than the cell length. Therefore, the ferroelectric liquid crystal compositions exhibited excellent orientation.
• ferroelectric liquid crystal compositions which exhibit good orientation and high-speed responsiveness, can be applied to a ferroelectric liquid crystal display device with a large capacity.

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• 1990
  • 1990-07-30 JP JP2204851A patent/JPH0488080A/ja active Pending
• 1991
  • 1991-07-26 EP EP19910306856 patent/EP0469800A3/en not_active Withdrawn
  • 1991-07-29 KR KR1019910013051A patent/KR920002743A/ko not_active Application Discontinuation

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